Adenoviral expression vectors

ABSTRACT

The present invention provides a recombinant adenovirus vector characterized by the partial or total deletion of adenoviral E2B function and having an expression cassette containing a heterologous sequence encoding a protein of interest inserted into the E1 region. Such vectors are designed to reduce or eliminate the occurrence of replication competent adenovirus contamination. Additionally, the expression cassette of the vector may contain one or more regulatory elements capable of increasing the expression of the heterologous sequence and/or reducing the expression of viral proteins. Such a reduction in expression of viral proteins reduces the cytotoxicty and immunogenicity of the adenovirus vectors when administered in vivo. Transformed production host cells and a method of producing recombinant proteins and gene therapy also are included within the scope of this invention.

REFERENCE TO CROSS RELATED APPLICATIONS

This application claims the benefit of priority under 35 USC 119(e) of provisional patent application U.S. Ser. No. 60/750,012 filed Dec. 12, 2005, the disclosure of which is hereby incorporated by reference in its entirety.

1. FIELD OF THE INVENTION

The present invention provides a recombinant adenovirus vector characterized by the partial or total deletion of adenoviral E2B function and having an expression cassette containing a heterologous sequence encoding a protein of interest inserted into the E1 region. Such vectors are designed to reduce or eliminate the occurrence of replication competent adenovirus contamination. Additionally, the expression cassette of the vector may contain one or more regulatory elements capable of increasing the expression of the heterologous sequence and/or reducing the expression of viral proteins. Such a reduction in expression of viral proteins reduces the cytotoxicty and immunogenicity of the adenovirus vectors when administered in vivo. Transformed production host cells and a method of producing recombinant proteins and gene therapy also are included within the scope of this invention.

2. BACKGROUND OF THE INVENTION

Recombinant adenovirus (rAd) vectors have desirable features for gene delivery, including wide tissue and cell tropism, the capacity to accommodate large expression cassettes and high transduction efficiency, and the capability to infect resting cells. The extremely low integrational tendency of adenoviruses is favourable as an additional safety aspect, since it minimizes the risk of insertion mutagenesis and oncogenic activation. A large number of different serotypes of human adenoviruses also provide choice of various viral sheaths with very different tropism. For example, group C viruses are extremely infectious for the liver or muscles, group D for cells of the central nervous system or group B for cells of the hemopoetic system. In addition, adenovirus is well suited for pharmaceutical development as the virus grows to high specific titers and scalable manufacturing processes have been established (Huyghe et al., 1995a; Shabram et al., 1997a).

Despite these decisive advantages the application possibilities for adenovirus vectors still remain limited. This is due to the fact that the adenoviruses vectors contain viral genes that are expressed in the target tissue. Direct toxicity, cut-off expression, inflammation of the tissue (Simon et al., 1993) and attack of cytotoxic T-lyphocytes are results which finally lead to destruction of infected cells. Numerous groups have tried to reduce the immunogenity of adenoviral vectors. E2 and E4 regions, which also have a transactivating function, where eliminated from the virus genome and were transferred into the helper cell line. However, it remains uncertain, whether these changes, which additionally cause reduction of the virus titres, are able to augment the duration of expression in vivo. As consequential continuation of this concept adenovirus vectors were developed in recent years, which are free from viral genes (Hardy et al., 1997; Kochanek et al., 1996; Kumar-Singh and Chamberlain, 1996; Mitani et al., 1995; Parks et al., 1996). However, such vectors are of little use for large scale pharmaceutical production.

3. SUMMARY OF THE INVENTION

The present invention provides a recombinant adenovirus vector characterized by the partial or total deletion of adenoviral E2B function and having an expression cassette containing a heterologous sequence encoding a protein of interest inserted into the E1 region. Such vectors are designed to have a reduction in the occurrence of replication competent adenovirus contamination. Additionally, the expression cassette of the vector may contain one or more elements capable of increasing the expression of the heterologous sequence and/or reducing the expression of viral proteins. Such a reduction in expression of viral proteins is intended to reduce the cytotoxicity and immunogenicity of the adenovirus vectors when administered in vivo.

The expression cassette of the vector is engineered to contain a heterologous sequence, i.e., a transgene, that encodes a protein of interest, or a functional fragment or mutant thereof. Such transgenes include, but are not limited to, those genes encoding any protein having therapeutic utililty, genes that replace defective genes in the target host cell, such as those responsible for genetic defect based diseased conditions; and/or genes which have therapeutic utility in the treatment of cancer, autoimmine and/or infectious diseases. Transformed host cells and a method of producing recombinant proteins and gene therapy also are included within the scope of this invention.

The expression cassette may additionally comprise one or more additional nucleic acid sequences that are designed to increase transgene expression, while reducing the expression of viral proteins. For example, the expression cassette may be engineered to contain an “insulator sequence” that functions to prevent the expression of genes found adjacent to the cassette from being activated. Thus, by insertion of an insulator sequence at the 3′ end of the expression cassette, expression of viral genes found adjacent to the expression cassette should remain low.

In yet another embodiment of the invention, the expression cassette may have the E1B polyA sequences substituted with heterologous polyA sequences that are know to enhance RNA polyadenylation and stability. Such substitutions may result in increased levels of transgene expression. PolyA sequences that may be utilized are well known to those of skill in the art and, include but are not limited to, bovine growth hormone polyA sequences.

In yet another embodiment of the invention, the expression cassette may additionally comprise a posttranscriptional regulatory element (PRE), such as those derived from mammalian hepadnaviruses. Such PRE sequences include, for example, those derived from hepatitis B virus (HBV) and woodchuck hepatitis virus (WHV).

In yet another embodiment of the invention, the expression cassette may additionally comprise an intron sequence inserted into the 5′ LTR of the expression cassette to increase transgene expression. Intron sequences, that may be used in the practice of the invention, are well known to those of skill in the art. Such sequences may be generated from known consensus splicing sequences.

The present invention also provides recombinant adenoviral vectors and therapeutic methods, for example, relating to gene therapy, vaccination, and the like, involving the use of such recombinants.

4. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a schematic diagram of the structure of the T2VP vector. As depicted, the vector contains deletions in the E1, E2B and E3 regions, and insertion of a transgene cassette into the E1 region of the virus. The transgene cassette includes the CMV promoter, the adenovirus 5 tripartite leader, a synthetic intron sequence 5′ to the transgene, i.e, rSEAP, a WPRE sequence, the BGH poly A sequence and a synthetic insulator sequence.

FIG. 2 depicts a comparison of SEAP expression in Ku-7 bladder cells infected with T2VP and other control viruses. In vitro testing demonstrates equivalent or increased expression of SEAP compared to control vectors.

FIG. 3 is an in vivo analysis of urine SEAP expression following intravesical delivery of T2VP and RCCB (control). As an example this experiment demonstrated that intravesical administration of T2VP to rat bladders improved duration of expression at a shortened redose time compared to RCCB, a standard E1-deleted adenovirus. There was an approximate ten fold decrease in SEAP expression between the initial and redose for the control RCCB vector, while the levels remained the same between the initial and redose of the T2VP vector. Anesthetized female Sprague-Dawley rats received an intravesical administration of recombinant adenovirus (˜5×10¹⁰ particles in 500 μL). Test articles were retained in the bladder for ˜1 hour and animals were permitted to void and recover. Timed urine samples beginning 24 hours after dosing were collected and analyzed for SEAP by ELISA. SEAP concentrations after the first intravesical administration are shown as solid symbols (Initial Dose). SEAP concentrations measured after a second intravesical dose (53 days later) are plotted as open symbols (53 Day Redose). Methods described in detail in Connor et al., 2005.

FIG. 4 is a schematic diagram of the structure of the T8BF vector compared to the IACB vector or rAdIFN vector (Benedict et al., 2004; Demers et al., 2002a; Demers et al., 2002b; Iqbal Ahmed et al., 2001; U.S. Pat. No. 6,210,939, the contents of which are herein incorporated by reference in their entirety). Showing differences in the E2b region and transgene cassette.

FIG. 5A-E presents the sequence and localization of features of the transgene cassette from T8BF.

FIG. 6A-K shows the full sequence of the T8BF adenovirus vector, including the transgene cassette (starting at nucleotide 365; see FIG. 5) comprising the sequence for interferon alpha 2b.

FIG. 7 is a comparison in vitro of interferon alpha 2b expression from IACB and T8BF. A549 cells were infected and analyzed 72 hours post infection. As indicated, an improvement in expression of interferon alpha 2b was observed when compared to the control virus IACB, which contains an E1 deletion.

FIG. 8 is an in vivo comparison of interferon alpha 2b expression from IACB and T8BF at both initial dose and 62 day redose. In this example, T8BF (circles) and IACB (squares) data is shown as mean ±SE for two experiments where n=5 (filled) and n=6 (open). Normal rats were dosed as described in FIG. 3 legend and Connor et al., 2005 and human interferon alpha 2b measured by ELISA.

5. DETAILED DESCRIPTION OF THE INVENTION

The present invention provides, inter alia, recombinant adenoviruses characterized by the partial or total deletion of the adenoviral E2B gene and having an expression cassette capable of encoding a protein of interest inserted into the E1 region. The subject vectors will find use in therapeutic applications, in which the vectors are employed to express a therapeutic nucleic acid, e.g. gene, into the genome of a target cell, i.e. gene therapy applications. The subject vectors may be used to deliver a wide variety of therapeutic nucleic acids. Therapeutic nucleic acids of interest include genes that replace defective genes in the target host cell, such as those responsible for genetic defect based diseased conditions; genes which have therapeutic utility in the treatment of cancer, autommune and/or infectious diseases and the like.

In accordance with the present invention there may be employed conventional molecular biology, microbiology, and recombinant DNA techniques within the skill of the art. Such techniques are explained in the literature. See, e.g., Sambrook, Fritsch & Maniatis, Molecular Cloning: A Laboratory Manual, Second Edition (1989) Cold Spring Harbor Laboratory Press, Cold Spring Harbor, N.Y. (herein “Sambrook, et al., 1989”); DNA Cloning: A Practical Approach, Volumes I and II (D. N. Glover ed. 1985); Oligonucleotide Synthesis (M. J. Gait ed. 1984); Nucleic Acid Hybridization (B. D. Hames & S. J. Higgins eds. (1985)); Transcription And Translation (B. D. Hames & S. J. Higgins, eds. (1984)); Animal Cell Culture (R. I. Freshney, ed. (1986)); Immobilized Cells And Enzymes (IRL Press, (1986)); B. Perbal, A Practical Guide To Molecular Cloning (1984); F. M. Ausubel, et al. (eds.), Current Protocols in Molecular Biology, John Wiley & Sons, Inc. (1994).

5.1 Terminology

As used herein, the term “adenovirus” refers to viruses of the genus adenoviridiae. The term “recombinant adenovirus” refers to viruses of the genus adenoviridiae capable of infecting a cell whose viral genomes have been modified through conventional recombinant DNA techniques. The term recombinant adenovirus also includes chimeric (or even multimeric) vectors, i.e. vectors constructed using complementary coding sequences from more than one viral subtype.

As used herein, the term “recombinant adenovirus vector(s)” refers to a vector construct comprising adenoviral nucleotide sequences and optionally, one or more heterologous nucleotide sequences. In a preferred embodiment, the recombinant adenovirus vectors comprise adenoviral nucleotide sequences that have reduced homology to the helper adenovirus nucleic acid sequences. In another preferred embodiment, the recombinant adenovirus vector encodes a replication-defective adenovirus. In accordance with this embodiment, the recombinant adenovirus vector may be engineered to comprise a mutated adenovirus genome by, e.g., introducing one or more mutations in an adenovirus genome (e.g., introducing deletions in one or more coding regions for adenoviral proteins).

As used herein, the term “adenoviridae” refers collectively to animal adenoviruses of the genus mastadenovirus including but not limited to human, bovine, ovine, equine, canine, porcine, murine and simian adenovirus subgenera. In particular, human adenoviruses include the A-F subgenera as well as the individual serotypes thereof. A-F subgenera including but not limited to human adenovirus types 1, 2, 3, 4, 4a, 5, 6, 7, 7a, 7d, 8, 9, 10, 11 (Ad11A and Ad11P), 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 34a, 35, 35p, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, and 91.

As used herein, the term “E1A gene” and “E1B region” refers to the immediate early genes of the adenovirus genome first transcribed following infection. For example, the E1A coding region spans nucleotide 560-1542 and the E1B coding region spans 1714-2242. As used herein, the term “E2B gene” refers to the early gene of the adenovirus genome that encodes the 140 kD DNA polymerase. The E2 region also encodes the precursor to the terminal protein (80 kD) that is cleaved during viral assembly to 55 kD while covalently bound to DNA. The E2B coding region spans nucleotide 8367-5197 of adenovirus type 5. GenBank® deposits of the complete human adenovirus type 5 genome are available, see for example, AY339865 and AC000008.

As used herein, the term “expression cassette” is used herein to define a nucleotide sequence capable of directing the transcription and translation of a heterologous coding sequence and the heterologous coding sequence to be expressed. An expression cassette comprises a regulatory element operably linked to a heterologous coding sequence so as to achieve expression of the protein product encoded by said heterologous coding sequence in the cell.

As used herein, the term “heterologous” in the context of nucleic acid sequences, amino acid sequences and antigens refers to nucleic acid sequences, amino acid sequences and antigens that are foreign and are not naturally found associated with a particular adenovirus.

As used herein, the term “operably linked” refers to a linkage of polynucleotide elements in a functional relationship. A nucleic acid sequence is “operably linked” when it is placed into a functional relationship with another nucleic acid sequence. For instance, a promoter or enhancer is operably linked to a coding sequence if it affects the transcription of the coding sequence. Operably linked means that the nucleotide sequences being linked are typically contiguous. However, as enhancers generally function when separated from the promoter by several kilobases and intronic sequences may be of variable lengths, some polynucleotide elements may be operably linked but not directly flanked and may even function in trans from a different allele or chromosome.

As used herein, the term “regulatory element” refers to promoters, enhancers, transcription terminators, insulator regions, silencing region, polyadenylation sites, intron sequences, post transcriptional regulatory elements and the like. The term “promoter” is used in its conventional sense to refer to a nucleotide sequence at which the initiation and rate of transcription of a coding sequence is controlled. The promoter contains the site at which RNA polymerase binds and also contains sites for the binding of regulatory factors (such as repressors or transcription factors). Promoters may be naturally occurring or synthetic. When the vector to be employed is a viral vector, the promoters may be endogenous to the virus or derived from other sources. The regulatory elements may be arranged so as to allow, enhance or facilitate expression of the transgene only in a particular cell type. For example, the expression cassette may be designed so that the transgene is under control of a promoter which is constitutively active, or temporally controlled (temporal promoters), activated in response to external stimuli (inducible), active in particular cell type or cell state (selective) constitutive promoters, temporal viral promoters or regulatable promoters.

As used herein, the term “infecting” means exposing the recombinant adenovirus to a complementing cell line under conditions so as to facilitate the infection of the producer cell with the recombinant adenovirus. In complementing cells which have been infected by multiple copies of a given virus, the activities necessary for viral replication and virion packaging are cooperative. Thus, it is preferred that conditions be adjusted such that there is a significant probability that the cells are multiply infected with the virus. An example of a condition which enhances the production of virus in the cell is an increased virus concentration in the infection phase. However, it is possible that the total number of viral infections per cell can be overdone, resulting in toxic effects to the cell. Consequently, one should strive to maintain the infections in the virus concentration in the range of 10⁶ to 10¹⁰, preferably about 10⁹, virions per ml. Chemical agents may also be employed to increase the infectivity of the cell line. For example, the present invention provides a method to increase the infectivity of cell lines for viral infectivity by the inclusion of a calpain inhibitor. Examples of calpain inhibitors useful in the practice of the present invention include, but are not limited to, calpain inhibitor 1 (also known as N-acetyl-leucyl-leucyl-norleucinal, commercially available from Boehringer Mannheim). Calpain inhibitor 1 has been observed to increase the infectivity of cell lines to recombinant adenovirus (see, e.g. U.S. Pat. No. 7,001,770 herein incorporated by reference in its entirety).

As used herein, the term “culturing under conditions to permit replication of the viral genome” means maintaining the conditions for complementation so as to permit the recombinant adenovirus to propagate in the cell. It is desirable to control conditions so as to maximize the number of viral particles produced by each cell. Consequently it will be necessary to monitor and control reaction conditions such as temperature, dissolved oxygen, pH, etc. Commercially available bioreactors such as the CelliGen Plus Bioreactor (commercially available from New Brunswick Scientific, Inc. 44 Talmadge Road, Edison, N.J.) have provisions for monitoring and maintaining such parameters. Optimization of infection, transfection and culture conditions will vary somewhat, however, conditions for the efficient replication and production of virus may be achieved by those of skill in the art taking into consideration, for example, the known properties of the producer cell line, properties of the virus and the type of bioreactor.

As used herein, the term “helper adenovirus nucleic acid sequence(s)” refers to a nucleic acid sequence(s) that: (i) provides viral functions for the replication of a recombinant adenovirus vector and/or its packaging into infectious virions; and (ii) is (are) not replicated or assembled into viral particles to a measurable degree.

As used herein, the terms, “recombinant adenovirus production cell line”, “recombinant adenovirus complementation cells”, and “recombinant adenovirus complementation cell lines” are synonyms and mean a cell able to propagate recombinant adenoviruses by providing viral functions for replication of a recombinant adenovirus and/or its packaging into infectious virions.

As used herein, the term “transfection” or “transformation” means the introduction of a nucleic acid into a cell. A host cell that receives the introduced DNA or RNA has been “transformed” and is a “transformant” or a “clone.” Examples of transformation methods which are very well known in the art include liposome delivery, electroporation, CaPO₄ transformation, DEAE-Dextran transformation, microinjection and viral infection.

5.2 Recombinant Adenovirus Constructs

The recombinant adenovirus vectors of the invention comprise adenoviral nucleotide sequences and optionally, one or more heterologous nucleotide sequences. In a preferred embodiment, the recombinant adenovirus vectors comprise adenoviral nucleotide sequences having decreased homology to the adenovirus nucleic acid sequences of the complementing cell lines. The lack of homology between the adenoviral helper nucleic acid sequences and recombinant adenovirus vectors reduces the possibility of the viral genome recombining to produce replication competent adenovirus. In a preferred embodiment, the recombinant adenovirus vector encodes a replication-defective adenovirus. In accordance with this embodiment, the recombinant adenovirus vector may be engineered to comprise a mutated adenovirus genome by, e.g., introducing one or more mutations in an adenovirus genome (e.g., introducing deletions in one or more coding regions for adenoviral proteins). Preferably, the mutations in the adenovirus genome result in lower levels of expression of adenoviral proteins than wild-type adenovirus. The reduction in adenoviral protein expression reduces the immune response to the adenoviral proteins in a subject.

In a specific embodiment, the recombinant adenovirus vector encodes an E1 deleted replication-defective adenovirus and comprises a mutated genome with a partial or complete (preferably, a complete) deletion of the E2B polymerase function, and includes a heterologous nucleotide sequence. In a preferred embodiment, the recombinant adenovirus vector encodes a replication-defective adenovirus and comprises a mutated genome with a partial or complete (preferably, a complete) deletion of the E1A coding region, E1B coding region, E2B polymerase coding region and includes a heterologous nucleotide sequence in the deleted E1 coding region.

In an embodiment of the invention, deletions in the E2B region include those sufficient to lead to the production of a non-functional DNA polymerase. In a preferred embodiment of the invention the deletion in the E2B region retains sequences that encode viral proteins on the opposite strand. Mutations, that may be used in the practice of the invention include, but are not limited to, the E2b deletion of nucleotides 7274 to about 7881 (see Amalfitano et al., 1998, herein incorporated by reference in its entirety). In yet another embodiment of the invention point mutations may be genetically engineered into the E2B coding region which result in a decrease in functional adenovirus polymerase expression. In a specific embodiment of the invention, the start codon of the E2B gene may be mutated to prevent translation of the E2B mRNA, thereby eliminating the function of E2B polymerase activity.

The heterologous nucleotide sequences can be introduced into any region of the genome (e.g., the amino or carboxy-termini). In a specific embodiment, a heterologous nucleotide sequence is introduced into one of the deleted adenoviral coding regions, such as the E1, E2B or E3 coding region, of the mutated adenoviral genome. In a preferred embodiment of the invention, the heterologous nucleotide sequence is introduced into the deleted E1 coding region of the mutated adenoviral genome.

In accordance with the invention, the recombinant adenovirus vectors comprise an adenoviral genome or a portion thereof obtained and/or derived from any adenoviridae or a combination of adenoviridae. In a preferred embodiment, the recombinant adenovirus vectors comprise an adenoviral genome or portion thereof obtained and/or derived from a human adenoviridae. In another preferred embodiment, the recombinant adenovirus vectors comprise an adenoviral genome or portion thereof obtained and/or derived from the human adenovirus serotype 2 or 5.

In one embodiment the recombinant adenovirus vector is derived from a human adenovirus serotype 5 and comprises deletions of the E1a, E1b and protein IX functions, and deletions in the E3 region (see, e.g., U.S. Pat. Nos. 6,210,939 and 5,932,210, herein incorporated by reference in their entirety) and the E2b region. By way of example, and not limitation, the recombinant adenovirus vector derived from a human adenovirus serotype 5 can comprise a deletion of base pairs 357 to about base pairs 4050, such as, for example, base pairs 360 to between about base pairs 4030, a deletion of base pairs 28,597 to between about base pairs 30,471 and a deletion in the E2b region as described in Amalfitano, A. et al (1998), herein incorporated by reference in its entirety.

In another embodiment, the recombinant adenovirus vector is derived from a human adenovirus serotype 5 and comprises deletions of the same adenoviral sequences as shown in the adenoviral vector in FIG. 6.

The present invention relates to recombinant adenovirus expression vectors comprising an “expression cassette” which is inserted into the mutated adenoviral genome. As used herein, the term “expression cassette” is defined as a nucleotide sequence capable of directing the transcription and translation of a heterologous coding sequence and the heterologous coding sequence to be expressed. An expression cassette comprises a regulatory element operably linked to a heterologous coding sequence so as to achieve expression of the protein product encoded by said heterologous coding sequence in the cell.

In an embodiment of the invention, the heterologous nucleotide sequence is obtained and/or derived from a source other than the recombinant adenovirus vector. In accordance with the invention, the heterologous nucleotide sequence may encode a moiety, peptide, polypeptide or protein possessing a desired biological property or activity.

In certain embodiments, the heterologous nucleotide sequence encodes a biological response modifier such as a cytokine, cytokine receptor, hormone, growth factor or growth factor receptor. Non-limiting examples of such biological response modifiers include interferon (IFN)-alpha, IFN-beta, IFN gamma, interleukin (IL-1), IL-2, IL-3, IL-4, IL-5, IL-6, IL-7, IL-9, IL-10, IL-12, IL-15, IL-18, IL-23, erythropoietin (EPO), basic fibroblast growth factor (bFGF), acidic fibroblast growth factor (aFGF), vascular endothelial growth factor (VEGF), platelet derived growth factor (PDGF), epidermal growth factor (EGF), thymic stromal lymphopoietin (TSLP), GM-CSF, TNFR and TNFR ligand superfamily members including TNFRSF 18 and TNFSF18. In a preferred embodiment the nucleotide sequence encodes an interferon, such as Interferon alpha 2b. (see, e.g. U.S. Pat. No. 6,835,557, herein incorporated by reference in its entirety).

In other embodiments, the heterologous nucleotide sequence encodes an antibody. In yet other embodiments, the heterologous nucleotide sequence encodes a chimeric or fusion protein.

In certain embodiments, the heterologous nucleotide sequence encodes an antigenic protein, a polypeptide or peptide of a virus belonging to a different species, subgroup or variant of adenovirus other than the species, subgroup or variant from which the recombinant adenovirus vector is derived. In certain embodiments, the heterologous nucleotide sequence encodes an antigenic protein, polypeptide or peptide obtained and/or derived from a pathogenic microorganism.

In yet another embodiment of the invention, the heterologous nucleotide sequence is a cancer therapeutic gene. Such genes include those that enhance the antitumor activity of lymphocytes, genes whose expression product enhances the immunogenicity of tumor cells, tumor suppressor genes, toxin genes, suicide genes, multiple-drug resistance genes, antisense sequences, and the like. Thus, for example, the adenoviral vector of this invention can contain a foreign gene for the expression of a protein effective in regulating the cell cycle, such as p53, Rb, or mitosin, or in inducing cell death, such as the conditional suicide gene thymidine kinase.

According to the invention, if the heterologous nucleotide sequence of the recombinant adenovirus vector is to be expressed in host cells, a transcriptional control element, also called a promoter/enhancer sequence, should be provided. The promoter/enhancer sequence may be widely active or may, alternatively, be tissue specific. The promoter/enhancer sequence may be derived from a non-adenovirus source or may be an adenovirus promoter. In a preferred embodiment, the promoter/enhancer sequences used to regulate the expression of the heterologous nucleotide sequence are not shared with those promoter/enhancer sequences that regulate the expression of the helper adenovirus nucleic acid sequences. In accordance with this embodiment, a promoter can be any promoter known to the skilled artisan. For example, the promoter can be a constitutive promoter, a tissue-specific promoter or an inducible promoter. Examples of promoters that may be used in accordance with the invention include: the SV40 early promoter (Benoist and Chambon, 1981), the promoter contained in the 3′ long terminal repeat of Rous sarcoma virus (Yamamoto et al., 1980), the herpes thymidine kinase promoter (Wagner et al., 1981), the regulatory sequences of the metallothionein gene (Brinster et al., 1982), the beta-actin promoter, the CMV promoter, the SR-alpha promoter, the hFer/SV40 promoter, the Elf-1 promoter, the Tet promoter, the Ecdysone promoter and a rapamycin promoter.

In a specific embodiment, a native promoter is utilized to regulate the expression of a nucleotide sequence encoding an adenoviral protein. In alternative embodiment, a promoter that is not native to the adenoviral gene encoding the protein being expressed (i.e., a heterologous promoter) is utilized to regulate the expression of the protein. In certain embodiments, the promoter is a constitutive promoter (e.g., a viral, cellular or hybrid constitutive promoter). In other embodiments, the promoter is an inducible promoter. In yet other embodiments, the promoter is a tissue-specific promoter.

In certain embodiments, it is desirable to use a constitutive promoter, such as a CMV promoter, β-actin promoter, SR-alpha promoter or hFer/SV40 promoter, to regulate the expression of the heterologous nucleotide sequence. In certain other embodiments, it is desirable to use a constitutive promoter, such as a RSV promoter, SV40 promoter or Elf-1 promoter, to regulate the expression of the heterologous nucleotide sequence. In yet other embodiments, it is desirable to use an inducible promoter, such as a Tet promoter or Ecdysone promoter, to regulate the expression of the heterologous nucleotide sequence of the adenovirus vector.

In yet another embodiment of the invention, an inducible promoter can be used in the adenoviral vector of the invention. These promoters will initiate transcription only in the presence of an additional molecule. Examples of inducible promoters include those obtainable from a β-interferon gene, a heat shock gene, a metallothionine gene or those obtainable from steroid hormone-responsive genes. Tissue specific expression has been well characterized in the field of gene expression and tissue specific and inducible promoters such as these are very well known in the art. These genes are used to regulate the expression of the foreign gene after it has been introduced into the target cell.

The desirable size of inserted non-adenovirus or heterologous nucleotide sequence is limited to that which permits packaging of the recombinant adenovirus vector into virions, and depends on the size of retained adenovirus sequences. The genome of a human adenovirus is approximately 36 kilobase pairs in length (measured to be 35938 nucleotides in length by (Davison et al., 2003). The total size of the recombinant adenovirus to be packaged into virions should be about 37735 nucleotides in length (about 105% of the normal genome length). Therefore, it may be desirable to exclude additional portions of the adenovirus genome, such as the E3 region, in the recombinant adenovirus vector in order to maximize expression of the inserted heterologous nucleotide sequence.

Insertion of a foreign gene sequence into a recombinant adenovirus vector of the invention can be accomplished by either a complete replacement of a viral coding region with a heterologous nucleotide sequence or by a partial replacement or by adding the heterologous nucleotide sequence to the viral genome. Complete replacement would probably best be accomplished through the use of PCR-directed mutagenesis. Briefly, PCR-primer A would contain, from the 5′ to 3′ end: a unique restriction enzyme site, such as a class IIS restriction enzyme site (i.e., a “shifter” enzyme; that recognizes a specific sequence but cleaves the DNA either upstream or downstream of that sequence); a stretch of nucleotides complementary to a region of the gene that is to be replaced; and a stretch of nucleotides complementary to the carboxy-terminus coding portion of the heterologous nucleotide sequence. PCR-primer B would contain from the 5′ to 3′ end: a unique restriction enzyme site; a stretch of nucleotides complementary to the gene that is to be replaced; and a stretch of nucleotides corresponding to the 5′ coding portion of the heterologous or non-native gene. After a PCR reaction using these primers with a cloned copy of the heterologous or non-native gene, the product may be excised and cloned using the unique restriction sites. Digestion with the class IIS enzyme and transcription with the purified phage polymerase would generate a RNA molecule containing the exact untranslated ends of the viral gene that carries now a heterologous or non-native gene insertion. In an alternate embodiment, PCR-primed reactions could be used to prepare double-stranded DNA containing the bacteriophage promoter sequence, and the hybrid gene sequence so that RNA templates can be transcribed directly without cloning.

When inserting a heterologous nucleotide sequence into the recombinant adenovirus vector of the invention, the intergenic region between the end of the coding sequence of the heterologous nucleotide sequence and the start of the coding sequence of the downstream gene can be altered to achieve a desired effect. As used herein, the term “intergenic region” refers to nucleotide sequence between the stop signal of one gene and the start codon (e.g., AUG) of the coding sequence of the next downstream open reading frame. An intergenic region may comprise a non-coding region of a gene, i.e., between the transcription start site and the start of the coding sequence (AUG) of the gene. This non-coding region occurs naturally in some viral genes.

In an embodiment of the invention, sequences referred to as “insulators” may be inserted into the expression cassette, in the intergenic region downstream of the heterologous nucleotide sequence (Di Simone et al., 2001; Martin-Duque et al., 2004a; Pluta et al., 2005; Puthenveetil et al., 2004; Qu et al., 2004; Rincon-Arano and Recillas-Targa, 2004; Takada et al., 2000) The insertion of such insulators can result in decreased expression of adenoviral proteins, as compared to wild type, which is useful in reducing the immunogenity and toxicity of the adenovirus vectors. Insulator sequences that may be used in the practice of the invention are well known to those of skill in the art and include, for example, hypersensitive site 4 (HS4) of the β-globin gene locus. The HS4 locus has been used in retroviruses (Emery et al., 2002; Jakobsson et al., 2004; Pannell and Ellis, 2001; Yannaki et al., 2002; Yao et al., 2003) and also adenovirus vectors (Cheng et al., 2004; Martin-Duque et al., 2004b; Steinwaerder and Lieber, 2000; Ye et al., 2003). The region of the HS4 locus being responsible for the control of gene expression through chromatin rearrangement and blocking activities has been attributed to the transcriptional modulator CTCF (Bell et al., 1999; Dunn and Davie, 2003; Dunn et al., 2003; Emery et al., 2002; Farrell et al., 2002; Jakobsson et al., 2004; Kanduri et al., 2002; Lewis and Murrell, 2004; Lutz et al., 2000; Mukhopadhyay et al., 2004; Pannell and Ellis, 2001; Recillas-Targa et al., 2002; Saitoh et al., 2000; Szabo et al., 2002; Thorvaldsen et al., 2002; Valadez-Graham et al., 2004; Yannaki et al., 2002; Yao et al., 2003; Yusufzai and Felsenfeld, 2004; Yusufzai et al., 2004; Zhang et al., 2004; Zhao and Dean, 2004). In an embodiment of the invention, an insulator comprising four head to tail copies of the CTCF binding site from the hypersensitive site 4 of the β-globin gene locus may be used as an insulator. In another embodiment, other synthetic insulator sequences (Bell et al., 2001; Brasset and Vaury, 2005; Zhao and Dean, 2004) may also be used.

In yet another embodiment of the invention, the E1B poly A signal sequence may be replaced with a heterologous polyA sequence that increases the polyadenylation and RNA stabilization of the heterologous gene. Such an increase in polyadenylation and RNA stabilization may result in more efficient expression of the heterologous gene product. In a non-limiting embodiment of the invention, the poly A signal sequences comprises sequences containing the following consensus sequences AATAAA or AATTAA. In an embodiment of the invention, the polyA sequence may be derived from a virus, such as the SV40 virus. In a specific embodiment of the invention the E1B polyA sequence may be substituted with the bovine growth hormone (BGH) polyadenylation signal sequence. (Xu et al., 2002; Youil et al., 2003) The BGH poly A sequence may be obtained by PCR from existing commercially available plasmids.

In yet another embodiment of the invention, the recombinant adenoviruses of the invention may include post-transcriptional regulatory element (PRE) that function to increase transgene expression. Such elements including, for example, the woodchuck hepatitis PRE (Donello et al., 1998), the hepatitis B virus PRE (Huang and Yen, 1994) or the herpes simplex PRE (Liu and Mertz, 1995) are inserted into the expression cassette at a location downstream of the heterologous gene (Appleby et al., 2003; Breckpot et al., 2003; Brun et al., 2003; Glover et al., 2002; Glover et al., 2003; Gropp et al., 2003; Mangeot et al., 2002; Robert et al., 2003; Schwenter et al., 2003; Werner et al., 2004; Xu et al., 2003; Yam et al., 2002; Zufferey et al., 1999).

The present invention also provides a recombinant adenovirus wherein the expression cassette is engineered to contain an intron sequence engineered into the 5′ untranslated region of the heterologous gene (Choi et al., 1991; Hermening et al., 2004; Lee et al., 1997; Xu et al., 2002; Xu et al., 2003). The intron sequences to be used in the practice of the invention can be generated from know consensus splicing sequences using, for example, PCR with primers that incorporate the necessary consensus splicing signals. Intron sequences include a 5′ splice donor site and a 3′ splice region that includes a branch point sequence and a 3′ splice acceptor AG site. The 3′ splice region may further comprise a polypyrimidine tract. Consensus sequences for the 5′ splice donor site and the 3′ splice region used in RNA splicing are well known in the art (See, Moore, et al., 1993, The RNA World, Cold Spring Harbor Laboratory Press, pp. 303-358). In addition, modified consensus sequences that maintain the ability to function as 5′ donor splice sites and 3′ splice regions may be used in the practice of the invention. Briefly, the 5′ splice site consensus sequence is AG/GURAGU (where A=adenosine, U=uracil, G=guanine, C=cytosine, R=purine and/=the splice site). The 3′ splice site consists of three separate sequence elements: the branch point or branch site, a polypyrimidine tract and the 3′ consensus sequence (YAG). The branch point consensus sequence in mammals is YNYURAC(Y=pyrimidine; N=any nucleotide). The underlined A is the site of branch formation. A polypyrimidine tract is located between the branch point and the splice site acceptor and is important for efficient branch point utilization and 3′ splice site recognition. Other pre-messenger RNA introns beginning with the dinucleotide AU and ending with the dinucleotide AC have been identified and referred to as U12 introns. U12 intron sequences as well as any additional sequences that function as splice acceptor/donor sequences may also be used to generate the expression cassette of the invention.

In yet another embodiment of the invention the 5′ untranslated region of the expression cassette comprises the adenovirus tripartite leader.

In one embodiment the expression vector comprises one or more heterologous nucleotide sequences, CMV promoters, a tripartite leader sequences, synthetic introns, WPRE sequences, polyA regions and CTCF binding sites. By way of example, and not limitation, the recombinant adenovirus vectors of the invention can comprise the expression cassette shown in FIG. 5.

The expression of the inserted heterologous nucleotide sequence can be determined by various indexes including, but not limited to, protein or mRNA expression levels, measured by following non-limiting examples of assays: immunostaining, immunoprecipitation and immunoblotting, enzyme-linked immunosorbent assay, nucleic acid detection (e.g., Southern blot analysis, Northern blot analysis, Western blot analysis), employment of a reporter gene (e.g., using a reporter gene, such as Green Fluorescence Protein (GFP) or enhanced Green Fluorescence Protein (eGFP), integrated to the viral genome the same fashion as the interested heterologous gene to observe the protein expression), or a combination thereof. Procedures of performing these assays are well known in the art (see, e.g. Flint et al., PRINCIPLES OF VIROLOGY, MOLECULAR BIOLOGY, PATHOGENESIS, AND CONTROL, 2000, ASM Press pp 25-56, the entire text is incorporated herein by reference).

For example, expression levels can be determined by infecting cells in culture with a recombinant adenovirus of the invention and subsequently measuring the level of protein expression by, e.g., Western blot analysis or ELISA using antibodies specific to the gene product of the heterologous nucleotide sequence, or measuring the level of RNA expression by, e.g., Northern blot analysis using probes specific to the heterologous sequence. Similarly, expression levels of the heterologous sequence can be determined by infecting an animal model and measuring the level of protein expressed from the heterologous nucleotide sequence of the recombinant virus of the invention in the animal model. The protein level can be measured by obtaining a tissue sample from the infected animal and then subjecting the tissue sample to Western blot analysis or ELISA, using antibodies specific to the gene product of the heterologous sequence. Further, if an animal model is used, the titer of antibodies produced by the animal against the gene product of the heterologous sequence can be determined by any technique known to the skilled artisan, including but not limited to, ELISA.

According to the invention, a recombinant adenovirus vector may be propagated in microorganisms, for example, as part of a bacterial plasmid or bacteriophage, in order to obtain large quantities of recombinant adenovirus vector.

5.4 Production of Recombinant Adenovirus

In accordance with the invention, recombinant adenovirus (preferably, recombinant replication-defective adenovirus) may be produced by co-transfecting an appropriate cell type with recombinant adenovirus vector and helper adenovirus nucleic acid sequences. Co-transfection may be performed by the DEAE dextran method (McCutchan and Pagano, 1968), the calcium phosphate procedure (Graham and van der Eb, 1973) or by any other method known in the art, including but not limited to microinjection, lipofection, and electroporation. Amounts of recombinant adenovirus vector and helper adenovirus nucleic acid sequences used in transfection are approximately 0.2 to 10 μg of DNA per 10⁶ cells, but may vary among different DNA constructs and cell types. Cells suitable for transfection include any cell line permissive for adenvirus infection, including, but not limited to HeLa cells, 293-D22 cells, A549 cells, HCT-15 cells, IGROV-1 cells, U87 cells and W162 cells.

Alternatively, a recombinant adenovirus complementing cell line may be transfected with recombinant adenovirus vector to produce of recombinant adenovirus (preferably, recombinant replication-defective adenovirus). In a specific embodiment, the present invention provides a method for producing recombinant adenovirus comprising culturing a recombinant adenovirus complementing cell line transfected with recombinant adenovirus vector under conditions so as to permit replication of the viral genome in the cell line, wherein the cell line comprises: (a) a first nucleic acid molecule comprising a nucleotide sequence encoding adenoviral E1A proteins; (b) a second nucleic acid molecule comprising a nucleotide sequence encoding an adenoviral E1B-55K protein (and preferably, does not comprise a nucleotide sequence encoding an adenoviral E1B-19K protein); and (c) a third nucleic acid molecule comprising a nucleotide sequence encoding an adenoviral E2B polymerase.

In a non-limiting embodiment of the invention, the SL0006 transformed cell line which has been engineered to express the E1A, E1B and E2B polymerase and which is described in U.S. patent application 60/674,488 and U.S. Publication No.: 2006/0270041 (the disclosures of which are herein incorporated by reference), can be used to propagate the recombinant adenoviruses of the invention. The SL0006 cell line is deposited under the Budapest Treaty with the American Type Culture Collection (ATCC), 10801 University Blvd., Manassas, Va., 20110-2209, USA, under ATCC Accession Number: PTA-6663.

Recombinant adenovirus of the present invention may be produced by any suitable method, many of which are known in the art (see, e.g., (Berkner and Sharp, 1983; Berkner and Sharp, 1984; Brough et al., 1992). In the preferred practice of the invention, the recombinant adenoviruses are derived from the human adenoviridae. In a preferred embodiment of the invention, the recombinant adenovirus is derived from the human adenovirus serotype 2 or 5.

In a preferred practice of the invention, the produced recombinant adenovirus is a replication-defective adenovirus comprising a mutated genome with a partial or complete (preferably, complete) deletion of the E1A coding region, E1B coding region, and E2B polymerase coding region, and includes one or more heterologous nucleotide sequences in the E1 region.

In another embodiment of the invention, the recombinant adenovirus is a replication-defective adenovirus and comprises a mutated genome with a partial or complete (preferably, complete) deletion of the E1A coding region, E1B coding region, E2B polymerase coding region, and E3 coding region, and includes one or more heterologous nucleotide sequences in the deleted E1 coding region.

In another embodiment of the invention, the recombinant adenovirus is a replication-defective adenovirus and comprises a mutated genome with a partial or complete (preferably, complete) deletion of the E1A coding region, E1B coding region, E2B polymerase coding region, and E4 coding region, and includes one or more heterologous nucleotide sequences in the deleted E1 coding region.

In another embodiment of the invention, the recombinant adenovirus is a replication-defective adenovirus and comprises a mutated genome with a partial or complete (preferably, complete) deletion of the E1A coding region, E1B coding region, E2B polymerase coding region, E3 coding region, and E4 coding region and includes one or more heterologous nucleotide sequences in the deleted E1 coding region.

The preferred recombinant adenoviruses of the present invention comprise viral DNA sequences that have reduced homology with the adenoviral DNA sequences in the recombinant adenovirus production cell, which reduces the possibility of the viral genome recombining with the cellular DNA to produce RCAs.

In certain embodiments, the quantity of recombinant adenovirus is titrated. Titrating the quantity of the adenovirus in the culture may be performed by techniques known in the art. In a particular embodiment, the concentration of viral particles is determined by the Resource Q assay as described by (Shabram et al., 1997b). As used herein, the term “lysis” refers to the rupture of the virus-containing cells. Lysis may be achieved by a variety of means well known in the art. For example, mammalian cells may be lysed under low pressure (100-200 psi differential pressure) conditions, by homogenization, by microfluidization, or by conventional freeze-thaw methods. Exogenous free DNA/RNA may be removed by degrecombinant adenovirusation with DNAse/RNAse.

Virus-containing cells may be frozen. Virus may be harvested from the virus-containing cells and the medium. In one embodiment, the virus is harvested from both the virus-containing cells and the medium simultaneously. In a particular embodiment, the virus producing cells and medium are subjected to cross-flow microfiltration, for example, as described in U.S. Pat. No. 6,146,891, under conditions to both simultaneously lyse virus-containing cells and clarify the medium of cell debris which would otherwise interfere with virus purification.

As used herein, the term “harvesting” means the collection of the cells containing the recombinant adenovirus from the media and may include collection of the recombinant adenovirus from the media. This may be achieved by conventional methods such as differential centrifugation or chromatographic means. At this stage, the harvested cells may be stored or further processed by lysis and purification to isolate the recombinant virus. For storage, the harvested cells should be buffered at or about physiological pH and frozen at −70° C.

Virus may also be harvested from the virus-containing cells and medium separately. The virus-containing cells may be collected separately from the medium by conventional methods such as differential centrifugation. Harvested cells may be stored frozen or further processed by lysis to liberate the virus. Virus may be harvested from the medium by chromatographic means. Exogenase free DNA/RNA may be removed by degrecombinant adenovirusation with DNAse/RNAse, such as BENZONASE (American International Chemicals, Inc.).

The virus harvest may be further processed to concentrate the virus by methods such as ultrafiltration or tangential flow filtration, for example, as described in U.S. Pat. Nos. 6,146,891; 6,544,769 and 6,783,983.

As used herein, the term “recovering” means the isolation of a substantially pure population of recombinant virus particles from the lysed producer cells and optionally from the supernatant medium. Viral particles produced in the cell cultures of the present invention may be isolated and purified by any method which is commonly known in the art. Conventional purification techniques such as chromatographic or differential density grecombinant adenovirusient centrifugation methods may be employed. For example, the viral particles may be purified by cesium chloride grecombinant adenovirusient purification, column or batch chromatography, diethylaminoethyl (DEAE) chromatography (Haruna et al., 1961; Klemperer and Pereira, 1959; Philipson, 1960), hydroxyapatite chromatography (U.S. Patent Application Publication Number US2002/0064860) and chromatography using other resins such as homogeneous cross-linked polysaccharides, which include soft gels (e.g., agarose), macroporous polymers based on synthetic polymers, which include perfusion chromatography resins with large “throughpores”, “tentacular” sorbents, which have tentacles that were designed for faster interactions with proteins (e.g., fractogel) and materials based on a soft gel in a rigid shell, which exploit the high capacity of soft gels and the rigidity of composite materials (e.g., Ceramic HyperD® F) (Broschetti, 1994; Rodrigues, 1997). In the preferred practice of the invention, the virus is purified by column chromatography in substantial accordance with the process of (Huyghe et al., 1995b) as described in Shabram, et al., U.S. Pat. No. 5,837,520 issued Nov. 17, 1998; see also U.S. Pat. No. 6,2661,823, the disclosures of which are herein incorporated by reference.

The recombinant adenovirus production cell lines producing virus may be cultured in any suitable vessel which is known in the art. For example, cells may be grown and the infected cells may be cultured in a biogenerator or a bioreactor. Generally, “biogenerator” or “bioreactor” means a culture tank, generally made of stainless steel or glass, with a volume of 0.5 liter or greater, comprising an agitation system, a device for injecting a stream of CO₂ gas and an oxygenation device. Typically, it is equipped with probes measuring the internal parameters of the biogenerator, such as the pH, the dissolved oxygen, the temperature, the tank pressure or certain physicochemical parameters of the culture (for instance the consumption of glucose or of glutamine or the production of lactate and ammonium ions). The pH, oxygen, and temperature probes are connected to a bioprocessor which permanently regulates these parameters. In other embodiments, the vessel is a spinner flask, a roller bottle, a shaker flask or in a flask with a stir bar providing mechanical agitation. In another embodiment, a the vessel is a WAVE Bioreactor (WAVE Biotech, Bridgewater, N.J., U.S.A.).

Recombinant adenoviruses may be propagated in the recombinant adenovirus production cell lines of the invention. Virus may be produced by culturing the cells; optionally adding fresh growth medium to the cells; inoculating the cells with the virus; incubating the inoculated cells; optionally adding fresh growth medium to the inoculated cells; and optionally harvesting the virus from the cells and the medium. Typically, when the concentration of viral particles, as determined by conventional methods, such as high performance liquid chromatography using a Resource Q column, as described in (Shabram et al., 1997b), begins to plateau, the harvest is performed.

Proteins produced by recombinant adenoviruses grown in the recombinant adenovirus production cell lines of the invention (e.g., adenovirus comprising a deletion of the E1A and E1B coding regions and comprising a heterologous nucleotide sequence, or adenovirus comprising a deletion of E1A, E1B and E2B polymerase coding regions and comprising a heterologous nucleotide sequence, adenovirus comprising a deletion of the E1A, E1B, E2B and E3 coding regions and comprising a heterologous nucleotide sequence, or adenovirus comprising a deletion of E1A, E1B, E2B polymerase coding regions, E3 and E4 coding regions and comprising a heterologous nucleotide sequence) may also be isolated and purified. Proteins, polypeptides and peptides may be purified by standard methods, including, but not limited to, salt or alcohol precipitation, affinity, preparative disc-gel electrophoresis, isoelectric focusing, high pressure liquid chromatography (HPLC), reversed-phase HPLC, gel filtration, cation and anion exchange and partition chromatography, and countercurrent distribution. Such purification methods are well known in the art and are disclosed, e.g., in “Guide to Protein Purification”, Methods in Enzymology, Vol. 182, M. Deutscher, Ed., 1990, Academic Press, New York, N.Y.

5.5 Utility of Recombinant Adenovirus

The recombinant adenoviruses of the invention can be used in vitro to express proteins, polypeptides and peptides of interest. The recombinant adenoviruses of the invention can also be used in gene therapy. The recombinant adenoviruses can be used for in vivo or ex vivo gene therapy. For in vivo gene therapy, recombinant adenovirus is directly administered to a subject. For ex vivo gene therapy, cells are infected with the recombinant adenovirus in vitro and then the infected cells are transplanted into the subject. In a specific embodiment, the recombinant adenovirus is directly administered in vivo, where a protein of interest is expressed.

In one embodiment, the present invention comprises a method for the treatment of cancer comprising administering a therapeutically effective amount of a recombinant adenovirus vector of the invention comprising one or more nucleotide sequences encoding a therapeutic protein to a subject. The recombinant adenovirus vectors of the invention comprising one or more nucleotide sequences encoding a therapeutic protein may be delivered to any cancerous tissue or organ using any delivery method known in the art, including, but not limited to intratumoral or intravesical administration. Examples of cancers that may be treated by the methods include, but are not limited to, carcinoma of the bladder and upper respiratory tract, vulva, cervix, vagina or bronchi; local metastatic tumors of the peritoneum; broncho-alveolar carcinoma; pleural metastatic carcinoma; carcinoma of the mouth and tonsils; carcinoma of the nasopharynx, nose, larynx, oesophagus, stomach, ovary, prostate colon and rectum, gallbladder, or skin; or melanoma or hematological cancers such as leukemia. By way of example, and not limitation, a recombinant adenovirus of the present invention comprising an expression cassette encoding interferon alpha 2b can be used in the treatment of bladder cancer. In one embodiment the recombinant adenovirus vector shown in FIG. 6 is used in the methods described herein to treat bladder cancer.

Non-limiting examples of therapeutically effective amounts of the recombinant adenovirus vectors of the invention comprising one or more nucleotide sequences encoding a therapeutic protein are in the range of between about 1×10⁸ particles/ml to about 1×10¹² particles/ml or between about 1×10⁹ particles/ml to about 1×10¹¹ particles/ml. In one embodiment, the recombinant adenovirus vector shown in FIG. 6 is administered to a subject with bladder cancer in the range of between about 1×10⁸ particles/ml to about 1×10¹² particles/ml or between about 1×10⁹ particles/ml to about 1×10¹¹ particles/ml.

In another embodiment, a cell is infected with a recombinant adenovirus and the resulting recombinant cell is administered to a subject. The resulting recombinant cells can be delivered to a subject by various methods known in the art. Recombinant blood cells (e.g., hematopoietic stem or progenitor cells) are preferably administered intravenously. The amount of cells envisioned for use depends on the desired effect, patient state, etc., and can be determined by one skilled in the art. In accordance with the invention, any cells which can be infected with a recombinant adenovirus can be for purposes of gene therapy. Non-limiting examples include epithelial cells (e.g., respiratory epithelial cells), endothelial cells, keratinocytes, fibroblasts, muscle cells, hepatocytes, blood cells (such as T lymphocytes, B lymphocytes, monocytes, macrophages, neutrophils, eosinophils, megakaryocytes, granulocytes), and various stem or progenitor cells (in particular, hematopoietic stem or progenitor cells, e.g., as obtained from bone marrow, umbilical cord blood, peripheral blood, fetal liver, etc.). In a preferred embodiment, the cell used for gene therapy is autologous to the subject. In an embodiment in which recombinant cells are used in gene therapy, the proteins encoded by the genome of the recombinant adenovirus are expressible by the cells or their progeny, and the recombinant cells are then administered in vivo for therapeutic effect.

The recombinant adenovirus of the present invention may be used to immunize a subject. For example, the recombinant adenovirus may be used to generate antibodies against a heterologous antigen encoded by the recombinant adenovirus. The amount of recombinant adenovirus to be used to immunize a subject and the immunization schedule will be determined by a physician skilled in the art and will be administered by reference to the immune response and antibody titers of the subject.

The antibodies generated against an antigen by immunization with a recombinant adenovirus may used in diagnostic immunoassays, passive immunotherapy, and generation of anti-idiotypic antibodies. The generated antibodies may be isolated by standard techniques known in the art (e.g., immunoaffinity chromatography, centrifugation, precipitation, etc.) and used in diagnostic immunoassays. The antibodies may also be used to monitor treatment and/or disease progression. Any immunoassay system known in the art may be used for this purpose including, but not limited to, competitive and noncompetitive assay systems using techniques such as recombinant adenovirusioimmunoassays, ELISA (enzyme-linked immunosorbent assays), “sandwich” immunoassays, precipitin reactions, gel diffusion precipitin reactions, immunodiffusion assays, agglutination assays, complement-fixation assays, immunorecombinant adenovirusiometric assays, fluorescent immunoassays, protein A immunoassays and immunoelectrophoresis assays, to name but a few.

The recombinant adenoviruses of the present invention can be used to produce antibodies for use in passive immunotherapy, in which short-term protection of a subject is achieved by the administration of pre-formed antibody directed against a heterologous antigen. The antibodies generated by the recombinant adenovirus of the present invention can also be used in the production of anti-idiotypic antibody. The anti-idiotypic antibody can then in turn be used for immunization, in order to produce a subpopulation of antibodies that bind the initial antigen (Jerne, 1974; Jerne et al., 1982).

In certain embodiments, the antibody produced by immunization with a recombinant adenovirus is modified prior to administration to a subject. For example, the antibody may be humanized and/or affinity matured.

5.6 Compositions and Methods of Administering Recombinant Adenovirus

The invention encompasses compositions comprising a recombinant adenovirus (preferably, replication-defective recombinant adenovirus) generated by the methods of the invention. In a preferred embodiment, the compositions are pharmaceutical compositions suitable for administration to a subject.

The pharmaceutical compositions of the present invention comprise an effective amount of recombinant adenovirus, and a pharmaceutically acceptable carrier. In a specific embodiment, the term “pharmaceutically acceptable” means approved by a regulatory agency of the Federal or a state government or listed in the U.S. Pharmacopeia or other generally recognized pharmacopeiae for use in animals, and more particularly in humans. The term “carrier” refers to a diluent, adjuvant, excipient, or vehicle with which the pharmaceutical composition is administered. Saline solutions and aqueous dextrose and glycerol solutions can also be employed as liquid carriers, particularly for injectable solutions. Suitable pharmaceutical excipients include starch, glucose, lactose, sucrose, gelatin, malt, rice, flour, chalk, silica gel, sodium stearate, glycerol monostearate, talc, sodium chloride, dried skim milk, glycerol, propylene, glycol, water, ethanol and the like. These compositions can take the form of solutions, suspensions, emulsion, tablets, pills, capsules, powders, sustained-release formulations and the like. These compositions can be formulated as a suppository. Oral formulation can include standard carriers such as pharmaceutical grecombinant adenoviruses of mannitol, lactose, starch, magnesium stearate, sodium saccharine, cellulose, magnesium carbonate, etc. Examples of suitable pharmaceutical carriers are described in “Remington's Pharmaceutical Sciences” by E. W. Martin. Such compositions will contain an effective amount of recombinant adenovirus, preferably in purified form, together with a suitable amount of carrier so as to provide the form for proper administration to the patient. The formulation should suit the mode of administration.

The amount of the pharmaceutical composition of the invention which will be effective in the treatment of a particular disorder or condition will depend on the nature of the disorder or condition, and can be determined by standard clinical techniques. In addition, in vitro assays may optionally be employed to help identify optimal dosage ranges. The precise dose to be employed in the formulation will also depend on the route of administration, and the seriousness of the disease or disorder, and should be decided according to the judgment of the practitioner and each patient's circumstances. Effective doses may be extrapolated from dose-response curves derived from in vitro or animal model test systems.

Non-limiting examples of therapeutically effective amounts of the recombinant adenovirus vectors of the invention comprising one or more nucleotide sequences encoding a therapeutic protein are in the range of between about 1×10⁸ particles/ml to about 1×10¹² particles/ml or between about 1×10⁹ particles/ml to about 1×10¹¹ particles/ml.

By way of example, and not limitation for the treatment of superficial bladder cancer in a subject, course of treatment comprising a dose of from 1××10¹⁰.particles/ml to about 1×10¹².particles/ml, most preferably approximately 1×10¹¹ particles/ml encoding interferon alpha.2b in a volume of approximately 100 ml is instilled intravesically for a period of approximately one hour. By way of example, and not limitation, an alternate course of treatment may comprise a dose of from 1××10 ¹⁰.particles/ml to about 1×10¹².particles/ml most preferably approximately 1×10¹¹ particles/ml encoding interferon alpha2b in a volume of approximately 100 ml is instilled intravesically for a period of approximately one hour followed by a second substantially equivalent dose within 7 days, 5 days, 4 days, 3 days, 2 days or on consecutive days following the first dose. Each course of treatment is repeatable, depending on the course of disease progression. In the case of intravesically administered recombinant vectors for the treatment of bladder cancer, optimal interferon gene expression is generally observed when the courses of treatment are distanced by at least 14 days, more preferably about 30 days, and most preferably about 90 days.

Methods of administration of the compositions include, but are not limited to, intradermal, intramuscular, intraperitoneal, intravenous, subcutaneous, intranasal, epidural, and oral routes. The pharmaceutical compositions of the present invention may be administered by any convenient route, for example by infusion or bolus injection, by absorption through epithelial or mucocutaneous linings (e.g., oral mucosa, rectal and intestinal mucosa, etc.) and may be administered together with other biologically active agents. Administration can be systemic or local. In addition, it may be desirable to introduce the pharmaceutical compositions of the invention into the lungs by any suitable route. Pulmonary administration can be employed, e.g., by use of an inhaler or nebulizer, and formulation with an aerosolizing agent.

In a specific embodiment, it may be desirable to administer the pharmaceutical compositions of the invention locally to the area in need of treatment; this may be achieved by, for example, and not by way of limitation, local infusion during surgery, topical application, e.g., in conjunction with a wound dressing after surgery, by injection, by means of a catheter, by means of a suppository, or by means of an implant, said implant being of a porous, non-porous, or gelatinous material, including membranes, such as sialastic membranes, or fibers. In one embodiment, administration can be by direct injection at the site (or former site) of a malignant tumor or neoplastic or pre-neoplastic tissue. In another embodiment the administration can be intravesicular administration.

In another embodiment, the pharmaceutical composition can be delivered in a controlled release system. In one embodiment, a pump may be used (Buchwald et al., 1980; Langer, 1983; Saudek et al., 1989; Sefton, 1987). In another embodiment, polymeric materials can be used (see Medical Applications of Controlled Release, Langer and Wise (eds.), CRC Pres., Boca Raton, Fla. (1974); Controlled Drug Bioavailability, Drug Product Design and Performance, Smolen and Ball (eds.), Wiley, New York (1984); (Langer and Peppas, 1983); (During et al., 1989; Howard et al., 1989; Levy et al., 1985). In yet another embodiment, a controlled release system can be placed in proximity of the composition's target, i.e., the lung, thus requiring only a fraction of the systemic dose (see, e.g., Goodson, 1984, in Medical Applications of Controlled Release, supra, vol. 2, pp. 115-138). Other controlled release systems are discussed in the review by (Langer, 1990).

In a specific embodiment, a composition of the invention is a vaccine or immunizing composition comprising a recombinant adenovirus (preferably, replication-defective recombinant adenovirus) generated by the methods of the invention, and a suitable excipient. Many methods may be used to introduce the vaccine compositions, these include but are not limited to intranasal, intratracheal, oral, intradermal, intramuscular, intraperitoneal, intravenous, and subcutaneous routes. It may be preferable to introduce the recombinant adenovirus vaccine composition via the natural route of infection of adenovirus.

Non-limiting examples of therapeutically effective amounts of the recombinant adenovirus vectors of the invention comprising one or more nucleotide sequences encoding a therapeutic protein are in the range of between about 1×10⁸ particles/ml to about 1×10¹² particles/ml or between about 1×10⁹ particles/ml to about 1×10¹¹ particles/ml.

In some embodiments it may be desirable to administer the recombinant adenovirus vector in conjunction with enhancing agents that facilitate the transfer of the nucleic acid encoding a therapeutic protein, for example interferon, to a target cell, such as, for example, a cancer cell. Examples of such delivery enhancing agents include detergents, alcohols, glycols, surfactants, bile salts, heparin antagonists, cyclooxygenase inhibitors, hypertonic salt solutions, and acetates. Alcohols include for example the aliphatic alcohols such as ethanol, N-propanol, isopropanol, butyl alcohol, acetyl alcohol. Glycols include glycerine, propyleneglycol, polyethyleneglycol and other low molecular weight glycols such as glycerol and thioglycerol. Acetates such as acetic acid, gluconic acid, and sodium acetate are further examples of delivery-enhancing agents. Hypertonic salt solutions like 1M NaCl are also examples of delivery-enhancing agents. Bile salts such as taurocholate, sodium tauro-deoxycholate, deoxycholate, chenodesoxycholate, glycocholic acid, glycochenodeoxycholic acid and other astringents such as silver nitrate may be used. Heparin-antagonists like quaternary amines such as protamine sulfate may also be used. Anionic, cationic, zwitterionic, and nonionic detergents may also be employed to enhance gene transfer. Exemplary detergents include but are not limited to taurocholate, deoxycholate, taurodeoxycholate, cetylpyridium, benalkonium chloride, Zwittergent 3-14 detergent, CHAPS (3-[(3-Cholamidopropyl)dimethylammoniol]-1-propanesulfon-ate hydrate), Big CHAP, Deoxy Big CHAP, Triton-X-100 detergent, C12E8, Octyl-B-D-Glucopyranoside, PLURONIC-F68 detergent, Tween 20 detergent, and TWEEN 80 detergent (CalBiochem Biochemicals). Particularly preferred enhancing agents and methods are described in Engler et al., U.S. Pat. No. 6,312,681, issued Nov. 6, 2001, Engler et al., U.S. Pat. No. 6,165,779, issued Dec. 26, 2000, and Engler et al., U.S. Pat. No. 6,392,069, issued May 21, 2002, the entire teachings of which are herein incorporated by reference. A particularly preferred enhancing agent useful in the practice of the present invention is a compound termed Syn3 of the Formula I in U.S. Pat. No. 6,392,069. Additional enhancing agents useful in the practice of the present invention include, but are not limited to, the compounds of the Formulas II, III, IV, and V and their pharmaceutically acceptable salts in WO2004/108088. By way of example, and not limitation, the enhancing agents may be administered concomitant with the vector or prior to the administration of the vector.

The compositions and methods of the present invention may be practiced alone or in combination with conventional chemotherapeutic agents or treatment regimens. Examples of such chemotherapeutic agents include inhibitors of purine synthesis (e.g., pentostatin, 6-mercaptopurine, 6-thioguanine, methotrexate) or pyrimidine synthesis (e.g., Pala, azarbine), the conversion of ribonucleotides to deoxyribonucleotides (e.g., hydroxyurea), inhibitors of dTMP synthesis (5-fluorouracil), DNA damaging agents (e.g., radiation, bleomycines, etoposide, teniposide, dactinomycine, daunorubicin, doxorubicin, mitoxantrone, alkylating agents, mitomycin, cisplatin, procarbazine) as well as inhibitors of microtubule function (e.g., vinca alkaloids and colchicine). Chemotherapeutic treatment regimens refers primarily to nonchemical procedures designed to ablate neoplastic cells such as radiation therapy. These chemotherapeutic agents may be administered separately or may be included with the formulations of the present invention for co-administration. The present invention may also be practiced in combination with conventional immunotherapeutic treatment regiments such as BCG in the case of superficial bladder cancer.

The present invention is not to be limited in scope by the specific embodiments described herein. Indeed, various modifications of the invention in addition to those described herein will become apparent to those skilled in the art from the foregoing description. Such modifications are intended to fall within the scope of the appended claims.

Patents, patent applications, publications, product descriptions, and protocols are cited throughout this application, the disclosures of which are incorporated herein by reference in their entireties.

PUBLICATIONS

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1. A recombinant adenoviral vector comprising (a) an expression cassette inserted in to the E1 region of the adenoviral vector, wherein said expression cassette comprises (i) a regulatory element operably linked to a first nucleic acid molecule comprising a nucleotide sequence encoding protein of interest; and (ii) one or more elements selected from the group consisting of an insulator sequence, a polyA signal sequence that is substituted for the E1B polyA signal sequence; and a posttranscriptional regulatory element; and (b) a mutation that deletes or inactivates the activity of the E2B polymerase.
 2. The vector of claim 1, wherein the expression cassette further comprises one or more elements selected from a CMV promoter, a tripartite leader sequence, a WPRE sequences a CTCF binding site.
 3. The vector of claim 1, wherein the nucleic acid sequence encodes an interferon.
 4. The vector of claim 3, wherein the interferon is interferon alpha 2b.
 5. The vector of claim 1, wherein the expression cassette is the expression cassette shown in FIG.
 5. 6. The vector of claim 1, wherein the vector comprises the sequence shown in FIG.
 6. 7. The vector of claim 1 derived from a human adenovirus serotype
 5. 8. The vector of claim 7, comprising a deletion beginning at nucleotide 357 and ending at nucleotide 4030 or 4050, a deletion beginning at nucleotide 28,597 and ending at nucleotide 30,471 and a deletion beginning at 28,597 and ending at nucleotide 30,471.
 9. A method for treating cancer comprising administering the vector of claim 1 to a subject in need of such treatment.
 10. The method of claim 9, wherein the cancer is bladder cancer.
 11. The method of claim 9, wherein the vector is administered in the range of between about 1×10⁸ particles/ml to about 1×10¹² particles/ml.
 12. The method of claim 11, wherein the vector is administered in the range of between about 1×10⁹ particles/ml to about 1×10¹¹ particles/ml.
 13. The method of claim 9, wherein the vector is administered in conjunction with an enhancing agent.
 14. The method of claim 13, wherein the enhancing agent is SYN-3. 